{{indexmenu_n>5}}

====== DSC or Buddy via AIS. ======

If  DSC or GPSGate Buddy-messages are available in an incoming NMEA 0183 data stream, OpenCPN will show them with their own icons, and they will show in the "AIS Target list". They are not a part of AIS, but are displayed the same way, for convenience.

DSC is used on all new VHF set (or should be!). More on [[http://en.wikipedia.org/wiki/Digital_Selective_Calling|Wikipedia.]] To use this feature, check that your VHF set outputs NMEA 0183, in a way that can be connected to OpenCPN.

GPSGate is a commercial **[[http://en.wikipedia.org/wiki/GpsGate|GPS tracking and sharing ]]**service[[http://en.wikipedia.org/wiki/GpsGate|.]] GPSGate Buddy Tracking is** ** **[[http://gpsgate.com/products/gpsgate_server_buddytracker|part of that service**.]]**

Make sure that Options--> AIS Targets -->"Play Sound on CPA/TCPA Alerts" box is ticked, otherwise the alarm sound (see below) will not be heard.

**If OpenCPN receives a DSC Distress call, an alarm will be triggered, both visually and by sound**.


{{opencpn:manual:dsc-alert.png?nolink&600}}

**A VHF/DSC distress call is treated in the same way as an AIS/SART call. Both should be treated as MAYDAY calls.** 

**Two different types of alerts.** 
DSC Distress alert, coming from a specific vessel, presumably by crew activating a switch on the transponder. These are occasionally seen as false alerts, for testing. For the second type look under AIS SART section. SART, which is a SearchAndRescueTransponder.  The MMSI starts with 97..... and will have Class: SART. This might be from a
PLB (and PLB-AIS) on man overboard, for instance.  PLB AIS devices are under the AIS SART type.

**Quick Reference** 


{{opencpn:manual:dsc-ok.png?nolink&45x44}}DSC Station. Only the DSC message received. The position contains only degrees and minutes of Latitude and Longitude.

{{opencpn:manual:dse1.png?nolink&}}DSC Station. DSC **and **DSE messages received. The DSE message contains the missing decimals of minutes of Latitude and Longitude. The result is a much more accurate position.

{{opencpn:manual:dsc-not-ok.png?nolink&45x42}}DSC Station transmitting a **distress** signal. **This is a "Mayday".** 

{{opencpn:manual:bud-icon.png?nolink&46x45}}GpsGate Buddy target.




A normal DSC target, is someone using a dsc-capable VHF

{{opencpn:manual:dsc-ok2.png?nolink&400x223}}

Distress message via DSC, Digital selective Calling, from an unidentified AIS target.

{{opencpn:manual:dsc_distress.jpg?nolink&400x260}}

A green Buddy target on an island.

{{opencpn:manual:gpsg_buddy.jpg?nolink&400x209}}

The AIS Target List View

{{opencpn:manual:dsc-list.png?nolink&800x280}}

Seven Green DSC Position Report Instances, Position displayed in yellow hover box

{{:opencpn:manual:dsc-7-instances.jpg?350}}


